1. Field of the Invention
The present invention relates to an image pickup apparatus which cuts out, and enlarges or reduces a part of an image represented by an image pickup signal obtained by performing image pickup, an image processing apparatus and a method for activating the image pickup apparatus.
2. Description of the Related Art
Electronic zoom processing for cutting out, and enlarging or reducing a part of an image represented by an image pickup signal has been conventionally proposed, and it is widely performed to acquire an electronically enlarged image by cutting out a part of a central part of an image and performing interpolation and the like.
By the way, super-wide-angle endoscopes aiming at increasing an angle of view have been proposed recently. An endoscope which acquires a front-field-of-view image from a front-view observation window arranged on a distal end face of a cylindrical portion and acquires a side-field-of-view image from a side-view observation window arranged on a circumferential face of the cylindrical portion, for example, as described in International Publication No. WO2011/055614 is given as an example. Since the super-wide-angle endoscope described in International Publication No. WO2011/055614 has a structure in which a nozzle portion configured to clean the front-view observation window and the side-view observation window, and the like are arranged along a part of the circumferential face of the cylindrical portion, it is inevitable that optical vignetting occurs in a part of a formed optical image (for example, a part of a side field of view here).